1. Field of the Invention
The present invention relates to the polymerization of olefins using a catalyst system comprising a compound of a Group IVB metal and an aluminoxane.
2. Description of the Prior Art
Various prior art references exist which describe olefin polymerization catalysts comprising a compound of a transition metal belonging to Group IVB of the Periodic Table and an aluminoxane. Included are U.S. Pat. Nos. 4,404,344, 4,542,199, 4,544,762, 4,665,208 and 4,752,597. Also included is PCT Publication No. WO 88/03932. It would be of commercial interest to achieve an increase in the activity of such catalysts.
U.S. Pat. No. 3,740,384 mentions use of 1,1,3,3-tetraphenylsiloxane-1,3-diol to improve the olefin polymerization activity of an organometallic zirconium complex. The catalyst described in this patent is devoid of an aluminoxane component.